Porous metal device for regenerating soft tissue-to-bone interface

ABSTRACT

The present disclosure relates, in some aspects, to orthopaedic implants for securing soft tissue to bone and methods for using the same. One particular implant comprises a first exposed porous surface region, having pores for promoting bone ingrowth, and a second exposed porous surface, having pores for promoting soft tissue ingrowth. At least some of the pores of the first exposed porous surface region may be seeded with osteocytic factors and at least some of the pores of the second exposed porous surface region may be seeded with fibrocytic factors. Such orthopaedic implants can advantageously facilitate regeneration of the soft tissue to bone interface.

CLAIM OF PRIORITY

This application is a continuation of U.S. patent application Ser. No.14/727,008, filed on Jun. 1, 2015, which is a continuation of U.S.patent application Ser. No. 13/679,041, filed on Nov. 16, 2012, nowissued as U.S. Pat. No. 9,055,977, which claims the benefit of priorityunder 35 U.S.C. §119(e) of Jiang et al., U.S. Provisional PatentApplication Ser. No. 61/561,475, entitled “POROUS METAL DEVICE FORREGENERATING SOFT TISSUE-TO-BONE INTERFACE”, filed on Nov. 18, 2011, andalso claims the benefit of priority under 35 U.S.C. §119(e) of Hoeman etal., U.S. Provisional Patent Application Ser. No. 61/699,373, entitled“POROUS METAL DEVICE FOR REGENERATING SOFT TISSUE-TO-BONE INTERFACE”,filed on Sep. 11, 2012, which are herein incorporated by reference inits respective entirety.

BACKGROUND 1. Field of the Disclosure

The present disclosure relates to orthopaedic implants. Moreparticularly, some aspects of the present disclosure relate toorthopaedic implants including an exposed open porous metal surface forsecuring soft tissue to bone.

2. Description of the Related Art

Soft tissue injuries, such as tendon and ligament tears, are commonfollowing traumatic injury or due to deterioration of joints. Repair oftendon and ligament injuries commonly requires surgical intervention. Insome cases, a surgeon will suture the torn ligament or tendon to bone.In other instances, a graft may be required to reconnect the tendon orligament to bone. Even after surgically repairing tendon and ligamentinjuries, optimal function of a joint may not fully be restored. In suchcases, revision surgical procedures are commonly required.

Problems associated with current treatment methods for tendon andligament injuries include an inability to provide adequate initialstiffness and strength of the repaired tendon or ligament, as well as aninability regenerate the bone to soft tissue interface. The interface atwhich the ligament or tendon contacts bone represents a potentialmechanical weak point of a repaired tendon or ligament. Thus,regeneration of the bone to soft tissue interface may enhance thesuccess rate of surgical repair of tendon and ligament injuries.

SUMMARY

Some aspects of the present disclosure relate to an orthopaedic implantand method of utilizing the same for securing soft tissue to bone. Theorthopaedic implants and methods of the present disclosure can beuseful, for example, to repair ligament injuries, such as anteriorcruciate ligament tears, and tendon injuries, such as rotator cuff andAchilles tendon tears. Moreover, some of the orthopaedic implants andmethods disclosed herein promote soft tissue and bone ingrowth withinthe orthopaedic implants, thereby facilitating regeneration of the softtissue to bone interface.

According to one embodiment of the present disclosure, an orthopaedicimplant for securing soft tissue to bone is presented which includes anopen porous metal body having an exterior that includes an exposedporous metal exterior surface suitable for contacting bone.Additionally, the body includes an opening in the exterior of the bodythat provides access to an exposed porous interior surface suitable forcontacting soft tissue. In some forms, the body will incorporate acannula or passage for receiving soft tissue such as where the body is afully cannulated tube, e.g., a cylindrical tube.

According to another embodiment of the present disclosure, anorthopaedic implant for securing soft tissue to bone is presentedincluding an open porous metal hollow body having an exposed porousinterior surface for contacting soft tissue. The open porous metalhollow body of the orthopaedic implant also includes an exposed porousexterior surface for contacting bone and a first opening dimensioned forreceiving a first end of a soft tissue graft. The open porous metalhollow body is also fully cannulated. In some configurations of theorthopaedic implant, the open porous metal hollow body is substantiallycylindrical in shape. In other configurations, however, the open porousmetal hollow body has a cross section selected from one of a circle,semi-circle, ellipse, oval or other arcuate shape. In yet otherconfigurations of the orthopaedic implant, the open porous metal hollowbody has a cross section selected from one of a triangle, square,rectangle or other polygon with four or more sides. Additionally,configurations of the orthopaedic implant may include the interiorsurface having a first coefficient of friction and the exterior surfacehaving a second coefficient of friction which is different than thefirst coefficient of friction.

According to another embodiment of the present disclosure, an implantfor securing soft tissue to bone is presented comprising a monolithicopen porous metal body, e.g., in the form of a sheet or tube. Themonolithic open porous metal body comprises a first soft tissueattachment layer having a plurality of pores with a first nominal porediameter and the first layer has a thickness, e.g., of between one andsix pore diameters, or between two and ten pore diameters, or betweenfive and twenty pore diameters, or less than thirty pore diameters, orhaving any suitable thickness. The monolithic open porous metal alsocomprises a second bone attachment layer having a plurality of poreswith a second nominal pore diameter and the second layer also has athickness, e.g., of between one and six pore diameters, or between twoand ten pore diameters, or between five and twenty pore diameters, orless than thirty pore diameters, or having any suitable thickness. Incertain forms, at least one of the first layer and second layer caninclude at least one fibrocytic factor or osteocytic factor. In someconfigurations of the orthopaedic implant, the pores of the first layerare seeded with a fibrocytic factor. Additionally, in someconfigurations, the pores of the second layer are seeded with anosteocytic factor. Further, some configurations of the orthopaedicimplant include the first nominal pore diameter being less than thesecond nominal pore diameter.

According to yet another embodiment of the present disclosure, animplant for securing soft tissue to bone is provided, comprising amonolithic open porous metal body. The monolithic open porous metal bodyincludes a soft tissue securing portion and a bone anchoring portion. Insome configurations of the orthopaedic implant, the bone anchoringportion includes a screw thread and the soft tissue securing portionincludes an eyelet with a passage therethrough. Further, according tothis configuration of orthopaedic implant, the fixation means has anouter surface with a first coefficient of friction and the passage hasan inner surface with a second coefficient of friction which is lessthan the first coefficient of friction.

In another embodiment, the present disclosure provides an implant forsecuring soft tissue to bone. This particular implant comprises atubular body that provides an inner passageway for receiving soft tissueof a patient. The inner passageway includes an interior side wall thatis provided by a first open porous metal structure with pores of a firstnominal pore diameter for suitably receiving soft tissue ingrowth. Thetubular body includes an exterior side wall that is provided by a secondopen porous metal structure with pores of a second nominal pore diametergreater than the first nominal pore diameter for suitably receiving boneingrowth. The inner passageway may or may not extend entirely throughthe tubular body. The inner passageway may or may not pass through thesecond open porous metal structure. The first open porous metalstructure may or may not be tubular. When tubular, the first open porousmetal structure can have any suitable shape, e.g., having a section witha circular or non-circular cross section. When the first open porousmetal structure is tubular, the second open porous metal structure mayor may not be tubular. In some forms, the second also will be tubularand will be positioned substantially concentrically around the tubularfirst open porous metal structure. In some other forms, the second openporous metal structure will be non-tubular (e.g., a sheet or layer withor without curvature) and will be positioned laterally adjacent thetubular first open porous metal structure. In some embodiments, thetubular body will include a side wall thickness that extends between theinterior side wall of the inner passageway and the exterior side wall ofthe tubular body, and this thickness will be provided entirely by openporous metal.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of thisdisclosure, and the manner of attaining them, will become more apparentand the disclosure itself will be better understood by reference to thefollowing description of embodiments of the disclosure taken inconjunction with the accompanying drawings, wherein:

FIG. 1 is an enlarged view of the structure of open porous metalaccording to the instant disclosure;

FIG. 2a is a cross-sectional view of an embodiment of open porous metalhaving larger pore sizes proximate the first exposed porous surfaceregion and smaller pore sizes proximate the second exposed poroussurface region;

FIG. 2b is another cross-sectional view of an embodiment of open porousmetal having larger pore sizes proximate the first exposed poroussurface region and smaller pore sizes proximate the second exposedporous surface region with an interface substrate separating theplurality of pores proximate the first exposed porous surface regionfrom the plurality of pores proximate the second exposed porous surfaceregion;

FIG. 3a is a cross-sectional view illustrating an ACL graft secured to acondyle of a femur with an orthopaedic implant according to the presentdisclosure;

FIG. 3b is a cross-sectional view illustrating an ACL graft secured to acondyle of a femur with another embodiment of an orthopaedic implantaccording to the present disclosure;

FIG. 4 is a perspective view illustrating a rotator cuff tendon securedto a humerus with an orthopaedic implant according to the presentdisclosure;

FIG. 5a is a perspective view illustrating an Achilles tendon secured toa bone in the ankle with an orthopaedic implant according to the presentdisclosure;

FIG. 5b is a perspective view illustrating an Achilles tendon secured toa bone in the ankle with another embodiment of an orthopaedic implantaccording to the present disclosure;

FIG. 6 is a perspective view illustrating a rotator cuff tendon securedto a humerus with another orthopaedic implant according to the presentdisclosure;

FIG. 7 is a scanning electron microscopy image of a porous tantalum discutilized in the Examples presented herein;

FIG. 8 is a scanning electron microscopy image of human osteoblastgrowth within a porous tantalum disc utilized in the Examples presentedherein, including arrows showing cell proliferation along the peripheryof the pores of the porous tantalum discs;

FIG. 9 is a scanning electron microscopy image of human fibroblastgrowth within a porous tantalum disc utilized in the Examples presentedherein, including arrows showing cell proliferation along the peripheryof the pores of the porous tantalum disc;

FIG. 10 presents two bar graphs illustrating osteoblast and fibroblastcell proliferation, respectively, on the porous tantalum disc utilizedin the Examples disclosed herein, compared to the control titanium disc;

FIG. 11 is a side view of an orthopaedic implant according to oneembodiment of the present disclosure with soft tissue of a patientpositioned in the implant;

FIG. 12a is a perspective view of an orthopaedic implant according toanother embodiment of the present disclosure; and

FIG. 12b is a top view of the orthopaedic implant shown in FIG. 12a .Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplifications set out hereinillustrate exemplary embodiments of the disclosure and suchexemplifications are not to be construed as limiting the scope of thedisclosure in any manner.

DETAILED DESCRIPTION

Introduction.

Some aspects of the present disclosure generally relate to orthopaedicimplants for securing soft tissue to bone and methods of utilizing theorthopaedic implants disclosed herein. In some embodiments, theorthopaedic implants disclosed herein comprise an open porous metalwhich defines an exposed porous surface particularly suited forcontacting bone, and an exposed porous surface particularly suited forcontacting soft tissue. Advantageously, these orthopaedic implants andsome of the methods disclosed herein can be used to promote theregeneration of the soft tissue to bone interface.

Open Porous Metal.

The orthopaedic implants disclosed herein are comprised of open porousmetal 100, shown in FIG. 1. According to some embodiments of theorthopaedic implants disclosed herein, open porous metal 100 maycomprise all or a substantial portion of the implant. Additionally, openporous metal 100 comprises exposed porous metal surfaces of theorthopaedic implants which, as described herein, are particularly suitedfor contacting bone and soft tissue.

Referring to FIG. 1, an illustrative embodiment of open porous metal 100is depicted. As shown, open porous metal 100 generally includes a largeplurality of ligaments 102 defining open voids (i.e., pores) or channels104 therebetween. The open voids between ligaments 102 form a matrix ofcontinuous channels 104 having few or no dead ends, such that growth ofsoft tissue and/or bone through open porous metal 100 is substantiallyuninhibited. Open porous metal 100 may include up to 75%-85% or morevoid space therein. Thus, open porous metal 100 may comprise alightweight, strong porous structure which is substantially uniform andconsistent in composition, and provides a matrix into which soft tissueand bone may grow to regenerate and strengthen anchoring of soft tissueto bone at the soft tissue to bone interface.

According to some configurations of the instant disclosure, the exposedporous metal surfaces of the orthopaedic implants disclosed hereincomprise open porous metal 100. For example, with reference to FIGS. 2aand 2b , first surface 106 and second surface 108 of open porous metal100 may comprise the exposed porous metal surfaces of the orthopaedicimplants disclosed herein. As depicted, the terminating ends ofligaments 102 (comprising open porous metal 100), referred to herein asstruts 150, define first surface 106 and second surface 108. Struts 150generate a high coefficient of friction along first surface 106 andsecond surface 108 (comprising the exposed porous metal surfaces of openporous metal 100). Further, struts 150 impart an enhanced affixationability to the exposed porous metal surfaces of open porous metal 100for adhering to bone and soft tissue.

Open porous metal 100 may be made of a highly porous biomaterial usefulas a bone substitute and/or cell and tissue receptive material. Forexample, according to embodiments of the instant disclosure, open porousmetal 100 may have a porosity as low as 55%, 65%, or 75% or as high as80%, 85%, or 90%. An example of open porous metal 100 is produced usingTrabecular Metal™ Technology generally available from Zimmer, Inc., ofWarsaw, Ind. Trabecular Metal™ is a trademark of Zimmer, Inc. Such amaterial may be formed from a reticulated vitreous carbon foam substratewhich is infiltrated and coated with a biocompatible metal, such astantalum, by a chemical vapor deposition (“CVD”) process in the mannerdisclosed in detail in U.S. Pat. No. 5,282,861 and in Levine, B. R., etal., “Experimental and Clinical Performance of Porous Tantalum inOrthopedic Surgery”, Biomaterials 27 (2006) 4671-4681, the disclosuresof which are expressly incorporated herein by reference. In addition totantalum, other metals such as niobium or alloys of tantalum and niobiumwith one another or with other metals may also be used. Further, otherbiocompatible metals, such as titanium, a titanium alloy, cobaltchromium, cobalt chromium molybdenum, tantalum, or a tantalum alloy mayalso be used.

Additionally, embodiments of open porous metal 100 may comprise aTi-6A1-4V ELI alloy, such as Tivanium® Alloy which is available fromZimmer, Inc., of Warsaw, Ind. Tivanium® is a registered trademark ofZimmer, Inc. Open porous metal 100 may also comprise a fiber metal pador a sintered metal layer, such as a CSTi™, Cancellous-StructuredTitanium™ coating or layer, for example. CSTi™ porous layers aremanufactured by Zimmer, Inc., of Warsaw, Ind. CSTi™ is a trademark ofZimmer, Inc.

In other embodiments, open porous metal 100 may comprise an open cellpolyurethane foam substrate coated with Ti-6A1-4V alloy using a lowtemperature arc vapor deposition process. Ti-6A1-4V beads may then besintered to the surface of the Ti-6A1-4V-coated polyurethane foamsubstrate. Additionally, another embodiment of open porous metal 100 maycomprise a metal substrate combined with a Ti-6A1-4V powder and aceramic material, which is sintered under heat and pressure. The ceramicparticles may thereafter be removed leaving voids, or pores, in thesubstrate. Open porous metal 100 may also comprise a Ti-6A1-4V powderwhich has been suspended in a liquid and infiltrated and coated on thesurface of a polyurethane substrate. The Ti-6A1-4V coating may then besintered to form a porous metal structure mimicking the polyurethanefoam substrate. Further, another embodiment of open porous metal 100 maycomprise a porous metal substrate having particles, comprising alteredgeometries, which are sintered to a plurality of outer layers of themetal substrate.

Additionally, open porous metal component 100 may be fabricatedaccording to electron beam melting (EBM) and/or laser engineered netshaping (LENS). For example, with EBM, metallic layers (comprising oneor more of the biomaterials, alloys, and substrates disclosed herein)may be coated (layer by layer) on an open cell substrate using anelectron beam in a vacuum. Similarly, with LENS, metallic powder (suchas a titanium powder, for example) may be deposited and coated on anopen cell substrate by creating a molten pool (from a metallic powder)using a focused, high-powered laser beam.

Open porous metal 100 may also be fabricated such that it comprises avariety of densities in order to selectively tailor the structure forparticular applications. In particular, as discussed in theabove-incorporated U.S. Pat. No. 5,282,861, open porous metal 100 may befabricated to virtually any desired density, porosity, and pore size(e.g., pore diameter), and can thus be matched with the surroundingnatural tissue in order to provide an improved matrix for tissueingrowth and mineralization.

Additionally, according to the instant disclosure, open porous metal 100may be fabricated to comprise substantially uniform porosity, density,and/or void (pore) size throughout, or to comprise at least one of poresize, porosity, and/or density being varied. For example, open porousmetal 100 may have a different pore size and/or porosity at differentregions, layers, and surfaces of open porous metal 100. The ability toselectively tailor the structural properties of open porous metal 100enables tailoring of open porous metal 100 for distributing stress loadsthroughout the surrounding tissue and promoting specific tissue ingrownwithin open porous metal 100.

Referring to FIGS. 2a and 2b , two embodiments of open porous metal 100comprising different pore sizes and porosity at different regions orsurfaces, are shown. With reference to FIG. 2a , open porous metal 100 acomprises first layer 101 a, second layer 103 a, first exposed surfaceregion 106 a, interface region 107 a, and second exposed porous surfaceregion 108 a. As illustrated, the nominal pore size of open porous metal100 a is relatively greater in first layer 101 a and at first exposedporous surface region 106 a as compared to second layer 103 a and secondexposed porous surface region 108 a. In some embodiments of open porousmetal 100 a, the alteration in pore size and porosity may graduallyoccur between first layer 101 a and second layer 103 a to form agradually increasing or decreasing pore size gradient. In otherembodiments of open porous metal 100 a, the change in pore size andporosity may be defined and localized at interface region 107 a, such asillustrated in FIG. 2 a.

Referring to FIG. 2b , another illustrative embodiment of open porousmetal 100 is provided. As shown in FIG. 2b , open porous metal 100 b,according to the instant disclosure, may comprise first layer 101 b,second layer 103 b, first exposed porous surface region 106 b, interfaceregion 107 b, and second exposed porous surface region 108 b. Interfaceregion 107 b of open porous metal 100 b comprises interface substrate110 positioned between first layer 101 b having greater pore size anddecreased porosity, and second layer 103 b having smaller pore size andgreater porosity. According to the embodiment of open porous metal 100depicted in FIG. 2b , first layer 101 b may be affixed to first surface112 of interface substrate 110 and second layer 103 b is affixed tosecond surface 114 of interface substrate 110. First layer 101 b andsecond layer 103 b may be diffusion bonded to first surface 112 andsecond surface 114 of interface substrate 110, respectively, usingapplied pressure at an elevated temperature for an appreciable period oftime.

Embodiments of open porous metal 100, such as illustrated in FIGS. 2aand 2b , may comprise a reticulated vitreous carbon (RVC) substrate of auniform pore size having a biocompatible metal, such as tantalum,infiltrated and coated thereon such as described in theabove-incorporated U.S. Pat. No. 5,282,861. According to the instantdisclosure, in order to form a porous metal having varying pore sizes, agreater amount of the biocompatible metal may be infiltrated and coatedon the carbon substrate in the second layer than in the first layer,resulting in the second layer having decreased pore size. This may beaccomplished by masking a portion of the carbon substrate during theinfiltration and deposition process, or, following an initial extent ofinfiltration and deposition of the metal, by at least partially fillinga sacrificial material into the pores of one of the layers, followed bycarrying out further infiltration and deposition of the metal into thepores of the other layer and then removing the sacrificial material.

With regard to open porous metal 100 b, illustrated in FIG. 2b , firstlayer 101 b and second layer 103 b may also be affixed to first surface112 and second surface 114 of interface substrate 110, respectively, byan infiltration and deposition welding process in which the substrates,perhaps following an initial extent of infiltration and deposition ofthe metal into the substrates as separate components, are held againstone another followed by exposing the combined substrate to a furtherextent of infiltration and deposition of the metal to concurrently coatand thereby fuse the substrates together. In a further embodiment, thesubstrates may be fused together by a resistance welding process usinglocalized heat generated through electric resistance.

According to exemplary embodiments of the orthopaedic implants disclosedherein, first exposed porous surface region 106 of open porous metal 100may comprise a bone contacting surface and second exposed porous surfaceregion 108 of open porous metal 100 may comprise a soft tissuecontacting surface. According to these embodiments, the voids or pores(defining channels 104) at first exposed porous surface region 106 maycomprise pore diameters of as low as approximately 40, 60 or 100 μm toas high as approximately 250, 300, or 350 μm, any value there between,or any value within any range delimited by any pair of the foregoingvalues, for example. Additionally, the pores at second exposed poroussurface region 108 may comprise diameters, of as low as approximately 5,10, or 15 μm to as high as approximately 100, 200, or 300 μm, any valuethere between, or any value within any range delimited by any pair ofthe foregoing values, for example.

Additionally, it should also be understood from the instant disclosurethat the voids (pores) within one of, or both of, first layer 101 andsecond layer 103 of open porous metal 100 may comprise varied diametersat different depths within first layer 101 and second layer 103. By wayof example, the plurality of pores at second exposed porous surfaceregion 108 may comprise diameters of approximately 200-300 μm. However,the pore diameters may gradually decrease within second layer 103 suchthat at as little as 2, 3, or 4, to as high as 13, 14, or 15 poredepths, or any value there between, within second layer 103, forexample, the plurality of pores may comprise diameters of approximately5 to 15 μm. Likewise, it should also be understood from the instantdisclosure that the pore diameter may gradually increase within firstlayer 101 or second layer 103. Selective tailoring of pore diameters,disposed at different depths within first layer 101 and second layer103, according to the instant disclosure, provides an osteoconductivestructure and promotes osteogenic and osteoinductive activity, as wellas providing a fibroconductive structure and promoting fibrogenic andfibroinductive activity, within the orthopaedic implants and therebyfacilitates the regeneration of the soft tissue to bone interface.

Bone and Soft Tissue Growth Factors and Agents.

In addition to comprising selectively tailored pore diameters atdifferent regions throughout open porous metal 100, open porous metal100 of the orthopaedic implants disclosed herein may also be combinedwith various bone and soft tissue growth factors or agents. For example,one or more of osteogenic, osteoinductive, angiogenic, angioinductive,fibrogenic, and/or fibroinductive factors or agents may be applied, orcoated, on a portion of the exposed porous surfaces of the orthopaedicimplants. Further, one or more bone and soft tissue growth factors oragents may be disposed within channels 104 proximal the exposed poroussurfaces of open porous metal 100.

Exemplary bone and soft tissue growth factors or agents which may becombined with the orthopaedic implants disclosed herein include, growthfactors influencing the attraction, activation, proliferation,differentiation, and organization of all bone cell types such asosteocytes, osteoclasts, osteoblasts, odentoblasts, cementoblasts, andprecursors thereof (e.g., stem cells). Additionally, the bone and softtissue growth factors or agents disclosed herein include growth factorsinfluencing the attraction, proliferation, differentiation, andorganization of soft tissue cell types such as fibrocytes, fibroblasts,chondrocytes, tenocytes, ligament cells, and precursors thereof (e.g.,stem cells). Further, the bone growth factors disclosed herein alsoinclude angiogenic factors, such as vascular endothelial growth factor(VEGF) and angiopoietins for example.

According to the instant disclosure, exemplary bone growth factors oragents include, but are not limited to, bone morphogenic proteins (BMP)such as BMP-1, BMP-2, BMP-3, BMP-4, BMP-5, BMP-6, BMP-7, Transforminggrowth factor (TGF)-β, platelet derived growth factors, and epidermalgrowth factor, for example. Additionally, other bone and soft tissuegrowth factors or agents which may be combined with the orthopaedicimplants disclosed herein include bone proteins, such as osteocalcin,osteonectin, bone sialoprotein, lysyloxidase, cathepsin L, biglycan,fibronextin fibroblast growth factor (FGF), platelet derived growthfactor, calcium carbonate, and thrombospondin (TSP). Exemplary softtissue growth factors or agents which may be combined with theorthopaedic implants disclosed herein include fibroblast growth factors(FGF) such as FGF-I, FGF-II, FGF-9, insulin growth factor (IGF)-I,IGF-II, platelet derived growth factor, epithelial growth factors (EGF),and TGF-α, for example.

In addition to the bone and soft tissue growth factors described above,the orthopaedic implants disclosed herein may also be combined withother general cellular growth factors such as angiogenic growth factors,such as VEGF and angiopoietins, in order to promote and supportvascularization at and within the soft tissue to bone interface at theorthopaedic implant. Even further, the orthopaedic implants may becombined with various cell types, for example bone cells such asosteoblasts, osteoclasts, cementoblasts, and odentoblasts for exampleand/or various soft tissue cells, such as tenocytes, chondrocytes,fibrocytes, fibroblasts, and ligament cells. In addition to the variouscell types, and various bone and soft tissue growth factors and agentslisted above, the orthopaedic implants may also be combined with stemcells in order to further support regeneration of the soft tissue tobone interface at the orthopaedic implants.

According to exemplary configurations of the orthopaedic implantsdisclosed herein, first exposed porous surface region 106 (FIG. 2a ) andsecond exposed porous surface region 108 (FIG. 2b ) may include (e.g.,be coated with) one, or a mixture of bone and soft tissue growth factorsor agents. Additionally, one, or a mixture of, bone and soft tissuegrowth factors and agents may be disposed on or within channels 104 offirst layer 101 (proximal first exposed porous surface region 106) andsecond layer 103 (proximal second exposed porous surface region 108).Further, the specific bone and soft tissue growth factors and agentscoated on, and possibly disposed on or within portions of theorthopaedic implants, may be selectively tailored for promotion one ofeither soft tissue or bone growth (at a desired region of theorthopeadic implant).

According to some configurations of the orthopaedic implants disclosedherein, first exposed porous surface region 106 and second exposedporous surface region 108 may include (e.g., be coated with) differentbone and soft tissue growth factors and agents. Likewise, channels 104of first layer 101 (proximal first exposed porous surface region 106)and channels 104 of second layer 103 (proximal second exposed poroussurface region 108) may have differing bone and soft tissue growthfactors and agents disposed therein. For example, an orthopaedic implantaccording to the instant disclosure may include one, or a mixture of,osteoinductive and osteogenic growth factors coated on first exposedporous surface region 106 and disposed within channels 104 of firstlayer 101 (proximal first exposed porous surface region 106).Additionally, the orthopaedic implant may include one, or a mixture of,fibrogenic and fibroinductive growth factors coated on second exposedporous surface region 108 and disposed within channels 104 of secondlayer 103 (proximal second exposed porous surface region 108). Selectivetailoring of pore diameters throughout open porous metal 100, inaddition to selective coating of the exposed porous surfaces of theorthopaedic implants with bone and soft tissue growth factors asdisclosed herein, promotes regeneration of the soft tissue to boneinterface at the orthopaedic implants.

Treatment of an Anterior Cruciate Ligament Injury with an ExemplaryOrthopaedic Implant

Referring to FIG. 3a , an illustrative embodiment of orthopaedic implant200 comprising open porous metal 100 (FIG. 1) is depicted. As shown,orthopaedic implant 200 comprises an implant for securing an anteriorcruciate ligament (“ACL”) or ACL graft G to a bone F. Although FIG. 3adepicts orthopaedic implant 200 securing ACL graft G to a femur (boneF), it should be understood that orthopaedic implant 200 may also beutilized for securing ACL graft G to a tibia.

According to some configurations of the instant disclosure, orthopaedicimplant 200 may include first layer 201 (comprising first exposed poroussurface region 206 for contacting bone F) and second layer 203(comprising second exposed porous surface region 208 for contacting ACLgraft G). Although orthopaedic implant 200 is depicted in FIG. 3a ascomprising two layers (first layer 201 and second layer 203),configurations of orthopaedic implant 200 may also comprise a singlelayer structure.

As depicted in FIG. 3a , orthopaedic implant 200 also encircles graftsecuring tunnel 210 such that second exposed porous surface region 208outlines (e.g., provides a rim around) graft securing tunnel 210.Additionally, while FIG. 3a depicts orthopaedic implant 200 as beingsubstantially tubular with a circular cross-section, configurations oforthopaedic implant 200 may include other forms such as square,rectangular, and oval. In this regard, tubular or tube-like structureswith cross sections of any suitable two-dimensional rectilinear orcurvilinear shape may be utilized. Further, configurations oforthopaedic implant 200, according to the instant disclosure, may beflexible such that graft securing tunnel 210 can be compressed, therebyallowing second exposed porous surface 208 to contact ACL graft G alongsubstantially all surfaces of ACL graft G when positioned within graftsecuring tunnel 210.

Configurations of orthopaedic implant 200 may also comprise open porousmetal 100 (FIG. 1) having different pore sizes and porosity at differentregions or surfaces of orthopaedic implant 200, such as shown in FIGS.2a and 2b for example. According to some configurations of orthopaedicimplant 200, the plurality of pores (voids) within first layer 201proximal first exposed porous surface region 206 may comprise nominalpore diameters which are greater than the plurality of pores (voids)within second layer 203 proximal second exposed porous surface region208. According to an exemplary configuration of orthopaedic implant 200,the plurality of pores within first layer 201 proximal first exposedporous surface region 206 may comprise pore diameters of as low asapproximately 40, 60, or 100 μm to as high as approximately 250, 300, or350 μm, any value there between, or any value within any range delimitedby any pair of the foregoing values, for example, whereas the pluralityof pores within second layer 203 proximal second exposed porous surfaceregion 208 may comprise pore diameters as low as approximately 5, 10, or15 μm to as high as approximately 200, 250, or 300 μm, any value therebetween, or any value within any range delimited by any pair of theforegoing values,.

In addition to comprising open porous metal 100 (FIG. 1) with differentpore sizes and porosities at different regions or surfaces,configurations of orthopaedic implant 200 may also comprise differentpore sizes and porosity at different depths throughout open porous metal100. For example, orthopaedic implant 200 may comprise open porous metal100 having pores at first exposed porous surface region 206 with porediameters of approximately 300 μm to 400 μm, for example, whereas thepores disposed 3 to 6 pore diameters within first layer 201 comprisepore diameters of approximately 100 μm to 300 μm. Similarly, orthopaedicimplant 200 may comprise open porous metal 100 (FIG. 1) having pores atsecond exposed porous surface region 208 comprise pore diameters ofapproximately 200 μm to 300 μm, for example, whereas the pores disposed3 to 6 pore diameters within second layer 203 comprise pore diameters ofapproximately 15 μm to 50 μm. As explained herein, variation of porediameters throughout first layer 201 and second layer 203 allowsorthopaedic implant 200 to provide an optimal matrix for providing anosteoconductive and fibroconductive structure and promoting osteogenicand fibrogenic activity, as well as osteoinductive and fibroinductiveactivity, at select positions within, and along, orthopaedic implant200.

Additionally, orthopaedic implant 200 may be combined with various boneand soft tissue growth factors or agents as discussed above. Forexample, a configuration of orthopaedic implant 200 may include amixture of one or more bone and growth factors coated on at least one offirst and second exposed porous surface regions 206, 208. Additionally,a mixture of one or more bone and soft tissue growth factors may bedisposed within channels 104 of first and second layers 201, 203proximal first and second exposed porous surface regions 206, 208.

According to another configuration of orthopaedic implant 200, firstexposed porous surface region 206 may be coated with one or more bonegrowth factors or agents, while second exposed porous surface region 208may be coated with one or more soft tissue growth factors or agents.Additionally, channels 104 (FIG. 1) of first layer 201 proximal firstexposed porous surface region 206 may include one or more bone growthfactors or agents disposed therein, while channels 104 of second layer203 proximal second exposed porous surface region 208 may include one ormore soft tissue growth factors or agents disposed therein. As detailedherein, combining orthopaedic implant 200 with select mixtures of boneand soft tissue growth factors and agents (at various positions alongand within orthopaedic implant 200), enhances the regeneration of softtissue to bone interface.

In use, during surgical repair of an ACL injury, orthopaedic implant 200is placed within bone tunnel 220. Bone tunnel 220 is created duringsurgery, though reaming, drilling, or any method known in the art, forplacement of orthopaedic implant therein. Although bone tunnel 220 isshown in FIG. 3a as extending substantially through a condyle of femurF, it should be understood that bone tunnel may extend only partiallywithin femur F as well.

As depicted in FIG. 3a , first end 212 of ACL graft G is insertedthrough first opening 215, defined by orthopaedic implant 200, andpositioned within graft securing tunnel 210. According to configurationsof orthopeadic implant 200, first end 212 of ACL graft G may be securedwithin graft securing tunnel 210 by compressing orthopaedic implant 200such that substantially all of first end 212 of ACL graft G is contactedby second open exposed porous surface region 208 of orthopaedic implant200. According to other configurations of orthopaedic implant 200, firstend 212 of ACL graft G may be initially secured within graft securingtunnel 210 by way of a securing anchor, such as an anchor screw oranother type of anchoring device, for example. According to suchconfigurations, first end 212 of ACL graft is affixed to the anchor andthe anchor is then the secured within graft securing tunnel 210.Further, in some configurations, securing anchors may be comprised inpart or entirely of open porous metal 100 (FIG. 1) as described herein.

Upon securing first end 212 of ACL graft G within graft securing tunnel210, orthopaedic implant 200 is positioned within bone tunnel 220. Asshown in

FIG. 3a , orthopaedic implant 200 is positioned within bone tunnel 220such that first exposed porous surface region 206 contacts bone F (whichhas been reamed or drilled) and second open porous surface 208 continuescontacting first end 212 of ACL graft G positioned within graft securingtunnel 210. As depicted in FIG. 3a , second end 214 of ACL graft Gextends out of graft securing tunnel 210 through first opening 215.

Orthopeadic implant 200 may be secured within bone tunnel 220 by way ofthe high coefficient of friction of first exposed porous surface 206,imparted by struts 150 (FIG. 1) of open porous metal 100 comprisingfirst exposed porous surface region 206, as described in detail in BobynJ. D., et al., “Characterization of new porous tantalum biomaterial forreconstructive orthopaedics”, Scientific Exhibition: 66^(th) AnnualMeeting of the American Academy of Orthopaedic Surgeons; 1999; AnaheimCalif., the disclosure of which is expressly incorporated herein byreference. First exposed porous surface region 206 may have acoefficient of friction (in contact with cancellous bone) which issixty-five percent greater than the coefficient of friction of corticalbone (in contact with cancellous bone), for example, as described indetail in Zhang Y. et al., “Interfacial frictional behavior: Cancellousbone, cortical bone, and a novel porous tantalum biomaterial”, Journalof Musculoskeletal Research, 1999; 3(4): 245-251, the disclosure ofwhich is expressly incorporated herein by reference.

According to configurations of orthopeadic implant 200 in which the highcoefficient of friction of first exposed porous surface region 206secures orthopaedic implant 200 within bone tunnel 220, the coefficientof friction of first exposed porous surface region 206 provides aninitial fixation of orthopaedic implant 200 to the bone F defining bonetunnel 210. The initial fixation secures orthopaedic implant 200 withinbone tunnel 220 for a period of time following implantation.Additionally, as explained above, open porous metal 100 further providesa matrix for bone ingrowth and mineralization. Bone ingrowth, withinopen porous metal 100 comprising first exposed porous surface region 206and first layer 201, thereby provides a rigid and secure secondaryfixation of orthopaedic implant 200 within bone tunnel 220.

Additionally, although not depicted, configurations of orthopaedicimplant 200 may be secured within bone tunnel 220 with an affixationscrew or with an adhesive. First end 212 of ACL graft G may also besecured within graft securing tunnel 210 by way of an affixation screwor an adhesive.

According to some configurations of orthopaedic implant 200, ACL graft Gmay be secured within graft securing tunnel 210 by way of the highcoefficient of friction of second exposed porous surface region 208,imparted by struts 150 (FIG. 1) of open porous metal 100 comprisingsecond exposed porous surface region 208. Further, the coefficient offriction of second exposed porous surface 208 may differ from thecoefficient of friction of first exposed porous surface region 206, ormay be approximately the same as the coefficient of friction of firstexposed porous surface region 206.

According to configurations of orthopeadic implant 200 in which thecoefficient of friction of second exposed porous surface region 208secures ACL graft G within graft securing tunnel 210, the coefficient offriction of second exposed porous surface region 208 provides an initialfixation of ACL graft G to the second exposed porous surface region 208.The initial fixation secures ACL graft G within graft securing tunnel210 for a period of time following implantation. However, as explainedabove, open porous metal 100 further provides a matrix for soft tissueingrowth and mineralization. Soft tissue ingrowth, within open porousmetal 100 comprising second exposed porous surface region 208 and secondlayer 203, thereby provides a rigid and secure secondary fixation of ACLgraft G within graft securing tunnel 210.

Referring to FIG. 3b , an illustrative configuration of orthopaedicimplant 200′ is depicted. As shown, orthopaedic implant 200′ comprisesscrew 250 or dowel (not shown) for securing an ACL graft G within bonetunnel 220′ of bone F. According to configurations of orthopaedicimplant 200′, screw 250 (or dowel) comprises open porous metal 100(FIG. 1) as described herein, advantageously promoting bone and/or softtissue ingrowth along all sides of, and throughout, screw 250.Additionally, orthopaedic implant 200′ may also be combined with one ormore bone and/or soft tissue growth factors or agents as discussedabove. Further, although FIG. 3b depicts orthopaedic implant 200′securing ACL graft G to a femur (bone F), it should be understood thatorthopaedic implant 200′ may also be utilized for securing ACL graft Gto a tibia.

While configurations of orthopaedic implant 200 and 200′, disclosedherein, have been described and depicted in use for repairing an ACL,configurations of orthopaedic implant 200 and 200′ may also be used inthe repair of other soft tissue injuries. For example, orthopaedicimplant 200 and 200′ may also be useful in repair of other kneeligaments, elbow ligaments and tendons, shoulder ligaments and tendons,biceps tendon and ligaments, and ankle ligaments and tendons.

Treatment of a Rotator Cuff Injury with an Exemplary OrthopaedicImplant.

Referring to FIG. 4, another illustrative embodiment of orthopaedicimplant 300 comprising open porous metal 100 is depicted. As shown,orthopaedic implant 300 comprises an implant for securing a rotator cuff(e.g., a subscapularis tendon or soft tissue graft G), or a portionthereof, to bone H (illustrated as a humerus).

According to some configurations of the instant disclosure, orthopaedicimplant 300 may include first exposed porous surface region 306 (forcontacting bone H) and second exposed porous surface region 308 (forcontacting soft tissue G). Orthopaedic implant 300, as depicted in FIG.4, may also include one or more anchoring screws 320 for securingorthopaedic implant 300 to bone H, and/or for securing graft G toorthopaedic implant 300. In some configurations of orthopaedic implant300, anchoring screws 320 may partially, or entirely, comprise openporous metal 100 (FIG. 1) as described herein.

As shown in FIG. 4, orthopaedic implant 300 comprises a thin sheet ofopen porous metal 100 (FIG. 1). According to some configurations,orthopaedic implant 300 may also be malleable such that, during asurgical procedure, orthopaedic implant 300 may advantageously be shapedand sized to a desired form. However, while orthopaedic implant 300 isdepicted and described herein as a thin sheet of open porous metal 100,configurations of orthopaedic implant 300 may also comprise open porousmetal 100 having a first layer and a second layer (similar toorthopaedic implant 200 depicted in FIG. 3a ). Additionally, whileorthopaedic implant 300 is depicted in FIG. 4 as being circular ordisc-like, configurations of orthopaedic implant 300 may comprise anynumber of forms such as a square, rectangle, oval, or other polygonalshape, for example.

Similar to embodiments of orthopaedic implant 200 (FIG. 3a ),orthopaedic implant 300 may comprise open porous metal 100 (FIG. 1)having different pore sizes and porosity at different regions orsurfaces of orthopeadic implant 300. For example, configurations oforthopaedic implant 300 may include the plurality of pores (voids) atfirst exposed porous surface region 306 having nominal pore diameterswhich are greater than the plurality of pores (voids) at second exposedporous surface region 308. Further, configurations of orthopaedicimplant 300 may also comprise different pore sizes and porosity atdifferent depths throughout open porous metal 100.

Additionally, as described herein, orthopaedic implant 300 may becombined with various bone and soft tissue growth factors or agents. Forexample, a configuration of orthopaedic implant 300 may include amixture of one or more bone and soft tissue growth factors coated on atleast one of first and second exposed porous surface regions 306, 308. Amixture of one or more bone and soft tissue growth factors may also bedisposed on or within channels 104 (FIG. 1) of open porous metal 100(comprising orthopaedic implant 300) proximal first and second exposedporous surface regions 306, 308. Further, configurations of orthopaedicimplant 300 may include first exposed porous surface region 306 beingcoated with one or more bone growth factors or agents, while secondexposed porous surface region 308 is coated with one or more soft tissuegrowth factor or agent.

In use, during surgical repair of a rotator cuff injury, orthopaedicimplant 300 may be secured to humerus H with anchoring screws 320. Priorto securing orthopaedic implant 300 to humerus H, a portion of humerus Hmay be prepared for securing orthopaedic implant 300 thereto, forexample, by reaming or grinding a portion of humerus H. As shown in FIG.4, orthopaedic implant 300 is secured to humerus H such that firstexposed porous surface region 306 contacts humerus H and second exposedporous surface region 308 contacts soft tissue G. Additionally, softtissue G may also be secured to second exposed porous surface region 308of orthopaedic implant 300 with anchoring screws 320. In someconfigurations of orthopaedic implant 300, soft tissue G may be securedto second exposed porous surface region 306 by way of the coefficient offriction of second exposed porous surface region 308, imparted by struts150 (FIG. 1) of open porous metal 100 comprising second exposed poroussurface region 308.

According to configurations of orthopeadic implant 300 in whichorthopeadic implant 300 is secured to bone H (and/or soft tissue G) byway of the high coefficient of friction of open porous metal 100, thecoefficient of friction provides an initial fixation for securingorthopaedic implant 300 to bone H (and/or soft tissue G). As explainedherein, the initial fixation secures orthopaedic implant 300 to bone H,and soft tissue G to (second exposed porous surface region 308 of)orthopaedic implant 300, for a period of time following implantation.However, ingrowth and mineralization of bone H within first exposedporous surface region 306 (and first layer 301), and soft tissue Gwithin second exposed porous surface region 308 (and second layer 303),thereby provides a rigid and secure secondary fixation of soft tissue Gto orthopaedic implant 300 and orthopaedic implant 300 to bone H.

While configurations of orthopaedic implant 300, disclosed herein, havebeen described and depicted for use in repairing a rotator cuff injury,configurations of orthopaedic implant 300 may also be useful in therepair of other soft tissue injuries. For example, orthopaedic implant300 may also be useful in repair of knee ligaments, elbow ligaments andtendons, and ankle ligaments and tendons.

Treatment of Achilles Tendon Injury with an Exemplary OrthopaedicImplant.

Further, orthopaedic implant 300 may also be useful in the repair ofAchilles tendon injures such as ruptures. Referring to FIGS. 5a and 5b ,illustrative embodiments of orthopaedic implant 300′ and 300″,respectively, are shown securing an achilles tendon or soft tissue graftG to a bone C in the ankle region, such as a calcaneus bone. Similar toconfigurations of orthopaedic implant 300 depicted in FIG. 4, above,orthopaedic implants 300′ and 300″ include first exposed porous surfaceregion 306′, 306″ (for contacting bone and/or soft tissue) comprised ofopen porous metal 100 (FIG.1). Orthopaedic implant 300′, shown in FIG.5a also includes second exposed porous surface region 308′ (forcontacting soft tissue) comprised of open porous metal 100.

Referring to FIGS. 5a and 5b , orthopaedic implants 300′, 300″ comprisea thin sheet of open porous metal 100 (FIG. 1). According to someconfigurations, orthopaedic implants 300′, 300″ may also be flexiblesuch that, during a surgical procedure, orthopaedic implants 300′, 300″may advantageously be shaped and sized to a desired form. Similar toconfigurations of orthopaedic implant 300, open porous metal 100comprising orthopaedic implants 300′, 300″ may also have different poresizes and porosity at different regions or surfaces, and at differentdepths throughout orthopaedic implants 300′, 300″. Further,configurations of orthopaedic implants 300′, 300″, as with orthopaedicimplant 300 (FIG. 4), may also be combined with one or more bone andsoft tissue growth factors or agents. Referring to FIG. 5a , in useduring surgical repair of an Achilles tendon injury orthopaedic implant300′ may be secured to a bone C in the ankle region of a leg, forexample a calcaneus bone. Advantageously, orthopaedic implant 300′ maybe shaped and sized (during the surgical procedure) to the size andcontour of the bone C. Further, orthopaedic implant 300′ may be securedto bone C by way of anchoring screws 320 or an adhesive. As shown,orthopaedic implant 300′ is secured to bone C such that first exposedporous surface region 306′ contacts bone C and second exposed poroussurface region 308′ contacts soft tissue G. Soft tissue G is secured tosecond exposed porous surface region 308′ of orthopaedic implant 300′,for example, with anchoring screws 320, surgical sutures, or the like.Additionally, in some configurations of orthopaedic implant 300′, softtissue G may be secured to first exposed porous surface region 306′ orby way of the coefficient of friction of second exposed porous surfaceregion 308′.

Referring to FIG. 5b , another configuration of orthopaedic implant 300″for use during surgical repair of an Achilles tendon injury is shown.According to FIG. 5b , soft tissue G is secured to bone C, or is heldagainst bone C by orthopaedic implant 300″. As shown, a portion of firstexposed porous surface region 306″ of orthopaedic implant 300″ contactssoft tissue G and presses soft tissue G against bone C. Portions offirst exposed porous surface region 306′ not contacting soft tissue G,are contoured to contact bone C. Orthopaedic implant 300′ may be securedto soft tissue G and bone C by way of anchoring screws 320 or anadhesive, such that the soft tissue G is also secured to bone C andfirst exposed porous surface region 306″ of orthopaedic implant 300″.Further, similar to configurations of orthopaedic implant 300′ shown inFIG. 5a , orthopaedic implant 300′ may advantageously be shaped andsized (during the surgical procedure) to a desired size and shape.

According to configurations of orthopeadic implant 300′, 300″ in whichorthopeadic implant 300′, 300′ is secured to bone C, and/or soft tissueG is secured to orthopaedic implant 300′, 300″, by way of the highcoefficient of friction of open porous metal 100, the coefficient offriction provides an initial fixation for securing orthopaedic implant300′, 300″ to bone C, and/or soft tissue G to orthopaedic implant 300′,300″. As explained above, the initial fixation secures orthopaedicimplant 300′, 300″ to bone C, and/or soft tissue G to orthopaedicimplant 300′, 300″, for a period of time following implantation.However, ingrowth and mineralization of bone C within first exposedporous surface region 306′, 306″, and soft tissue G within secondexposed porous surface region 308′ or first exposed porous surfaceregion 306″, thereby provides a rigid and secure secondary fixation ofsoft tissue G to orthopaedic implant 300′, 300″ and orthopaedic implant300′, 300″ to bone C.

Further, in some configurations of orthopaedic implant 300″, open porousmetal 100 (FIG. 1) comprising portions (or regions) of first exposedporous surface region 306″ may have different pore sizes and porosities.For example, the portion of first exposed porous surface region 306″contacting (and proximal to) soft tissue G may comprise pores (voids)having nominal pore diameters which are smaller than the pores of theportion of first exposed porous surface region 306″ which contact boneC.

Further, configurations of orthopaedic implant 300″ may also includeportions of first exposed porous surface region 306″ being combined withdifferent mixtures of bone and soft tissue growth factors and agents.For example, the portion of first exposed porous surface region 306″contacting (and proximal to) soft tissue G may be combined with one ormore soft tissue growth factors and agents, whereas the portion of firstexposed porous surface region 306″ contacting bone C may be combinedwith one or more bone growth factors or agents.

While configurations of orthopaedic implants 300″, 300″ disclosedherein, have been described and depicted for use in repairing anAchilles tendon injury, configurations of orthopaedic implants 300′,300″ may also be useful in the repair of other soft tissue injuries. Forexample, orthopaedic implants 300′, 300″ may also be useful in repair ofknee ligaments and tendons, elbow ligaments and tendons, and other ankleligaments and tendons.

Anchor Screw Embodiment of Orthopaedic Implant

Referring to FIG. 6, an illustrative embodiment of orthopaedic implant400 comprising a (or a plurality of) threaded anchor screw is shown.Orthopaedic implant 400 may partially or entirely comprise open porousmetal 100 (FIG. 1). As shown, orthopaedic implant 400 may be used forsecuring a rotator cuff (e.g., a subscapularis tendon or soft tissuegraft G), or a portion thereof, to bone H (illustrated as a humerus).

As shown in FIG. 6, orthopaedic implant 400 includes thread component402 (for contacting bone H and securing orthopaedic implant 400 therein)and aperture 404 (for receiving surgical sutures therethrough).

Additionally, according to some configurations of the presentdisclosure, open porous metal 100 (FIG. 1) comprising orthopaedicimplant 400 may have different pore sizes and porosity at differentregions or surfaces of orthopeadic implant 400. For example,configurations of orthopaedic implant 400 may include the plurality ofpores (voids) of thread component 402 having nominal pore diameterswhich are greater than the pore diameters of the pores proximal aperture404. Further, configurations of orthopaedic implant 400 may also includethe coefficient of friction of the open porous metal 100 definingaperture 404 being lower than the coefficient of friction of open porousmetal 100 comprising thread component 402.

Additionally, orthopaedic implant 400 may be combined with various boneand soft tissue growth factors or agents. For example, a configurationof orthopaedic implant 400 may include a mixture of one or more bone andsoft tissue growth factors coated on at least thread component 402.Further, configurations of orthopaedic implant 400 may also include oneor more soft tissue growth factor or agents coated on open porous metal100 defining aperture 404.

In use, during surgical repair of a rotator cuff injury, threadcomponent 402 of orthopaedic implant 400 may be securely screwed ordrilled into humerus H. As depicted in FIG. 6, one or more orthopaedicimplants 400 may be used. Surgical sutures 410 are threaded into a firstend of soft tissue graft G, and threaded through apertures 404 of theone or more orthopaedic implants 400. Soft tissue G is secured toorthopaedic implant 400, and tension applied to soft tissue G, by way ofsecuring surgical sutures 410 to orthopaedic implant 400 at apertures404.

While configurations of orthopaedic implant 400 have been described anddepicted herein as comprising a threaded anchor screw, embodiments oforthopaedic implant 400 may also comprise a dowel component and a dowelsleeve component (not shown). According to such configurations, softtissue G is secured to a first end of the dowel component. The dowelcomponent may then either be secured in a previously prepared bonetunnel, or may be secured within a dowel sleeve component secured in abone tunnel. As described herein, configurations of orthopaedic implant400 comprising a dowel and dowel sleeve component may also comprise openporous metal 100 (FIG. 1) having pores (voids) comprising varying porediameters. For example, configurations of orthopaedic implant 400 mayinclude open porous metal 100 of dowel component having pore diameterswhich are smaller than the pore diameters of open porous metal 100 ofdowel sleeve component.

Orthopaedic implant 400, while having been disclosed and describedherein for use in repairing rotator cuff injuries, may also be useful inthe repair of other soft tissue injuries. For example, orthopaedicimplant 400 may also be useful in repair of knee ligaments, elbowligaments and tendons, and ankle ligaments and tendons.

While this disclosure has been described as having exemplary designs,the present disclosure can be further modified within the spirit andscope of this disclosure. This application is therefore intended tocover any variations, uses, or adaptations of the disclosure using itsgeneral principles. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this disclosure pertains and which fallwithin the limits of the appended claims.

EXAMPLES

The Following Non-Limiting Examples Illustrate Various Features andCharacteristics of the Present Invention, Which is Not to Be Construedas Limited Thereto.

Example 1 Cellular Responses to Various Porous Tantalum Surfaces

I. Introduction.

The aim of the present example disclosed herein was to evaluateinteractions of human bone and soft tissue growth factors with an openporous metal according to the present disclosure. The examples providedherein further aim to evaluate osteoblast and fibroblast cellattachment, ingrowth and proliferation with an open porous metalaccording to the present disclosure.

II. Methods and Materials.

Circular porous tantalum discs having a diameter of approximately 10 mmand a thickness of 3 mm, were utilized in the Examples presented herein(see FIG. 7). Porous tantalum (Trabecular Metal, Zimmer, Inc., Warsaw,Ind.) is a form of open porous metal which has been utilized as animplantable material in clinical orthopaedic applications. The poroustantalum discs utilized in the present Examples were fabricatedaccording to a chemical vapor deposition/infiltration technique, asdescribed herein. The discs were also terminally sterilized using gammairradiation. Control discs comprised gamma sterilized polishednon-porous titanium discs having the same dimensions as the poroustantalum discs were also utilized.

Human osteoblasts (ATCC, CRL-1427) and human skin fibroblasts (ATCC,CRL-2522) were seeded onto the porous tantalum and Ti discs at a densityof 2×10⁴ cells per disc, and thereafter cultured in Eagle's MinimumEssential Medium with ten percent fetal bovine serum and one percentantibiotics at thirty-seven degrees Celsius in a humidified incubator.Following ten days of culture, cells on the discs were fixed withgluteraldehyde then dehydrated sequentially using ethanol series (50%,70%, 80%, 90%, 95%, and 100%) for ten minutes each. The discs werecoated with Pt/Pd and then viewed using scanning electron microscopy.Cell proliferation was quantified using the nonradioactive cellproliferation (MTS) assay from Promega (n=3). One-way ANOVA was used forperforming statistical analysis (p<0.05).

III. Results and Conclusions.

The Examples disclosed herein demonstrated that the porous tantalumdiscs supported attachment and proliferation of osteoblasts andfibroblasts. Referring to FIG. 8, growth of human osteoblasts upon aporous tantalum disc after ten days culture according to the presentExamples, is shown. As shown in FIG. 8, the osteoblasts producedextracellular matrix covering the TM surfaces and migrated into thepores of the discs.

Referring to FIG. 9, growth of human fibroblasts upon the poroustantalum discs after ten days culture according to the present Examples,is shown. As shown in FIG. 9, the majority of fibroblasts proliferatedon the porous tantalum skeleton and along the periphery of the pores.The fibroblasts produced less extracellular matrix than osteoblasts did,and a smaller percentage of fibroblasts migrated into the pores afterten days of culture.

Referring to FIG. 10, quantitative measurement of cell proliferation bynonradioactive cell proliferation (MTS) assay from Promega, after tendays of culture, is shown. As shown, cell proliferation (of bothosteoblasts and fibroblasts) on the porous tantalum discs wassignificantly greater than on the control titanium discs.

With reference now to FIG. 11, shown is another implant system 500 ofthe present disclosure that locates open porous metal components withdifferent characteristics, e.g., pore sizes and porosities, at differentregions or surfaces of the system. This illustrative system includes afirst element 550 and a second element 555. First element 550 includes afirst open porous metal structure 551 having a first exposed poroussurface region 552 that is particularly adapted for contacting softtissue or a soft tissue graft G. Second element 555 includes a secondopen porous metal structure 556 that can mimic one or more of thefeatures described above in relation to structure 100 a of FIG. 2a . Forexample, as illustrated, second open porous metal structure 556 providesa second exposed porous surface region 557 that is particularly adaptedfor contacting soft tissue or a soft tissue graft G and a third exposedporous surface region 558 that is adapted for contacting bone (notshown). In this regard, the nominal pore size of the second open porousmetal structure 556 can be relatively greater in third exposed poroussurface region 558 than in second exposed porous surface region 557 andfirst exposed porous surface region 552. Alternatively, structure 556could be configured with an interface substrate or layer similar to thatshown in element 100 b of FIG. 2b . Additionally, system 500 includes anoptional outermost coating or layer 560 (e.g., a pure titanium plate)that is essentially non-porous or measurably less porous than firststructure 551, for example, to inhibit cellular invasion and ingrowththereon and/or to protect surrounding tissues that might contact thelayer following implantation. In some preferred forms, layer 560 isbonded or otherwise connected to first structure 551, or it isintegrally formed into structure 551.

Continuing with FIG. 11, first structure 551 and second structure 556can each be shaped and configured in a variety of manners, for example,as a sheet, layer, disc, planar or non-planar plate (e.g., withcurvature), or any other suitable three-dimensional shape. Suchstructures can be particularly adapted for interacting with a tendon orother tissue G, for example, where a channel, passage or other space isprovided in one or both of the structures for receiving at least part ofthe tissue or graft. In some preferred forms, first structure 551 andsecond structure 556 both form part of a single or monolithic piece ofporous metal that is adapted to receive tissue G in or through themonolithic piece. In some other preferred forms, first structure 551 andsecond structure 556 are initially distinct and separate pieces (e.g.,solid discs or washers) that are later arranged together in the assemblyof system 500. Optionally, these separate pieces can be designed tocooperatively fit together, for example, where the pieces contact oneanother around the soft tissue or soft tissue graft G to fully orpartially enclose portions of the graft. When system components such asfirst structure 551 and second structure 556 are initially separatepieces, they can be held together in any suitable manner. Also in thisregard, the system or any individual part within the system can beconnected to the soft tissue G and/or to a bone in any suitable mannerincluding by bonding and/or utilizing any usable one- or multiple-piececonnection mechanism. For example, in one illustrative embodiment, oneor more screws are inserted through layer 560 toward a bone so that thescrew(s) pass through first structure 551 and second structure 556 (andoptionally also through a tendon, ligament, etc.) before entering thebone for securing the soft tissue within the system and securing thesystem to the bone.

FIG. 12A shows a generally rectangular parallelepiped open porous metalstructure 600 according to one embodiment of the present disclosure.Structure 600 includes an opening 601 in a first end 602 of thestructure that leads to an interior region 603 of the structure. In someaspects, structure 600 can mimic one or more of the features describedabove in relation to structure 100 a of FIG. 2a . For example, asillustrated, a relatively lower porosity region 604 of the structureprovides exposed interior porous surface walls 605 that are adjacentinterior region 603 and that are particularly adapted for contactingsoft tissue or a soft tissue graft, e.g., by inserting soft tissue intointerior region 603 through opening 601 during a surgical procedure. Arelatively higher porosity region 607 of the structure provides anexposed exterior porous surface wall 608 that is particularly adaptedfor contacting bone. In this regard, the nominal pore size is relativelygreater in exposed exterior porous surface wall 608 than in exposedinterior porous surface walls 605.

FIG. 12B shows an embodiment of structure 600 in which interior region603 provides a passage 610 extending fully through the structure fromfirst opening 601 to a second opening in an opposite end of thestructure. Such openings, interior regions, and passages can possess anysuitable size and shape, and even the structure itself can be anysuitable three-dimensional shape exhibiting rectilinear and/orcurvilinear features. Also, an optional coating or layer 611 as shown onstructure 600 in FIG. 12B is designed to inhibit cellular growth on thestructure. Such a coating or layer can be placed on select surfaces ofstructure 600 such as walls or regions in which cellular ingrowth orongrowth is not desired. In any suitable order, soft tissue can besecured in interior region 603 and in contact with exposed interiorporous surface walls 605, and exposed exterior porous surface wall 608can be secured against bone. In doing so, the structure 600 can beattached to the soft tissue and the bone in any suitable mannerincluding by bonding and/or utilizing any suitable one- ormultiple-piece connection mechanism. In one preferred method, a recessor indentation will be made in the bone for receiving and containing allor part of relatively higher porosity region 607.

1.-16. (canceled)
 17. A method of securing soft tissue to bone,comprising: locating an implant that is formed as a single implant piecealong an outer surface of a bone with a segment of soft tissue thatextends along the bone being received in a passage in the implant andwith the implant being secured to the outer surface of the bone, whereinthe implant includes a porous exterior surface contacting the outersurface of the bone, wherein the passage in which the segment of softtissue is received includes a porous inner wall contacting the segmentof soft tissue.
 18. The method of claim 17, wherein the porous innerwall of the implant is provided by a first open porous metal structurewith pores of a first nominal pore diameter for suitably receiving softtissue ingrowth, and wherein the porous exterior surface of the implantis provided by a second open porous metal structure with pores of asecond nominal pore diameter greater than said first nominal porediameter for suitably receiving bone ingrowth.
 19. The method of claim18, wherein the first nominal pore diameter is in the range of 5 μm to100 μm, and wherein the second nominal pore diameter is in the range of60 μm to 300 μm.
 20. The method of claim 17, wherein the segment of softtissue includes a tendon.
 21. The method of claim 17, wherein theimplant includes a non-porous exterior surface.
 22. The method of claim17, wherein the outer surface of the bone is a reamed or grindedsurface.
 23. The method of claim 17, wherein the porous exterior surfaceof the implant contacting the outer surface of the bone has a planarshape.
 24. The method of claim 17, wherein the porous exterior surfaceof the implant contacting the outer surface of the bone has a curvedshape.
 25. The method of claim 17, wherein the passage extends fullythrough the implant from a first opening in an outer surface of theimplant to a second opening in an outer surface of the implant.
 26. Themethod of claim 17, wherein the implant is in the form of a tube.
 27. Amethod of securing soft tissue to bone, comprising: positioning a softtissue segment inside a hollow tubular implant and in contact with aporous inner wall of the hollow tubular implant, the hollow tubularimplant also including a porous outer wall; and securing the porousouter wall of the hollow tubular implant to an outer surface of a bone,wherein the porous inner wall of the hollow tubular implant is providedby a first open porous metal structure with pores of a first nominalpore diameter for suitably receiving soft tissue ingrowth, and whereinthe porous outer wall of the hollow tubular implant is provided by asecond open porous metal structure with pores of a second nominal porediameter greater than said first nominal pore diameter for suitablyreceiving bone ingrowth.
 28. The method of claim 27, wherein the softtissue segment extends through a passage in the hollow tubular implanthaving a rectangular cross-sectional shape.
 29. The method of claim 27,wherein the hollow tubular implant is formed as a single implant piece.30. The method of claim 27, wherein the porous outer wall of the hollowtubular implant is secured to the outer surface of the bone before thesoft tissue segment is positioned inside the hollow tubular implant. 31.The method of claim 27, wherein the porous outer wall of the hollowtubular implant secured to the outer surface of the bone has a planarshape.
 32. The method of claim 27, wherein the hollow tubular implantincludes a non-porous exterior layer.
 33. The method of claim 32,wherein the non-porous exterior layer, the porous inner wall and theporous outer wall of the hollow tubular implant are provided by amonolithic implant piece.
 34. A method of securing soft tissue to bone,comprising: locating a monolithic implant piece and a segment of softtissue along an outer surface of a bone, wherein the segment of softtissue is received in a passage in the monolithic implant piece suchthat the segment of soft tissue contacts a porous inner wall of thepassage; and securing a porous exterior surface of the monolithicimplant piece to the outer surface of the bone.
 35. The method of claim34, wherein the monolithic implant piece includes a non-porous exteriorlayer.
 36. The method of claim 34, wherein the porous inner wall of themonolithic implant piece is provided by a first open porous metalstructure with pores of a first nominal pore diameter for suitablyreceiving soft tissue ingrowth, and wherein the porous exterior surfaceof the monolithic implant piece is provided by a second open porousmetal structure with pores of a second nominal pore diameter greaterthan said first nominal pore diameter for suitably receiving boneingrowth.
 37. The method of claim 34, wherein the porous exteriorsurface of the monolithic implant piece secured to the outer surface ofthe bone has a planar shape.
 38. The method of claim 37, wherein themonolithic implant piece has a tubular shape.